建德石灰石矿的噪声控制

以破碎、筛分工段为噪声的治理的重要环节,采取了相应的治理措施:设计隔音室;设置移动组装式隔声亭,选用低噪声设备;溜槽夹层填砂阻尼等.重视矿区规划,逐步实现功能分区,利用地形、地物、风向、绿化等有助于噪声自然衰减的外界条件,最大限度控制噪声危害。     

斜齿正时皮带传动的噪音和寿命

一种新的降低噪音的斜齿正时皮带已经被开发,本研究采用一种曲线齿廓分别设计了斜角为3°、5°和10°的三种皮带.把这些正时皮带的噪音和寿命与斜角为0°的常规正时皮带进行了比较.这些具有斜角为5°和10°的新型斜齿皮带的噪音比常规带低5 dB(A).设置装配张力传递动力时带松边张力最低,对各型带的寿命几乎相同.本研究结果表明,在实际应用中如果噪音是关键要素,则应选用斜齿带.     

机床空载功率和噪声的计算及应用探讨

参照同类机床空载和噪声的计算方法,以Ｃ６１４０车床为例,提出了降低其反转高速噪声的反向机构改进设计方案。     

商业车辆变速器的因素——性能,换档平顺性,噪时状况

Ｅｃｏｓｐｌｉｔ３系列的样机现代化表示的重要特征是不改变原来整个设计原理而能大大改进变速器的转矩能力、档平顺性和噪音状况。斜齿行星齿轮装置可使变速 降低１０分贝、在车辆变速败露首次采用了“锥形止推垫圈”技术,可使该行呈齿轮传动中的斜齿轮的轴向力自身消除。     

检测噪声图象边缘的概率集群识别方法

提出一种噪声图象中检测边缘的新方法。该方法从图象的灰度概率域入手,将概率谱分为两个等面积的集群。通过判定群间距离检测图象的边缘。理论分析与实验结果表明这种方法具有较强的噪声抑制能力和边缘提取能力。     

Characterization of vibration and acoustic noise in a gradient-coil insert

High-speed switching of current in gradient coils within high magnetic field strength magnetic resonance imaging (MRI) scanners results in high acoustic sound pressure levels (SPL) in and around these machines. To characterize the vibration properties as well as the acoustic noise properties of the gradient coil, a finite-element (FE) model was developed using the dimensional design specifications of an available gradient-coil insert and the concentration of the copper windings in the coil. This FE model was then validated using experimentally collected vibration data. A computational acoustic noise model was then developed based on the validated FE model. The validation of the finite-element analysis results was done using experimental modal testing of the same gradient coil in a free-free state (no boundary constraints). Based on the validated FE model, boundary conditions (supports) were added to the model to simulate the operating condition when the gradient-coil insert is in place in an MRI machine. Vibration analysis results from the FE model were again validated through experimental vibration testing with the gradient-coil insert installed in the MRI scanner and excited using swept sinusoidal time waveforms. The simulation results from the computational acoustic noise model were also validated through experimental noise measurement from the gradient-coil insert in the MRI scanner using swept sinusoidal time waveform inputs. Comparisons show that the FE model predicts the vibration properties and the computational acoustic noise model predicts the noise characteristic properties extremely accurately.     

用国产HiB钢,真正实现低损耗低噪声变压器的国产化

介绍了国产高磁感取向硅钢性能,并提出了制造低损耗、低噪声变压器的注意事项。     

大型电力变压器直流偏磁试验研究

以实例阐述了单相电力变压器的试验方法,研究了变压器在额定电压情况下发生直流偏磁时,励磁电流、运行噪声和振动等特性的变化。     

变压器发展中的一些新技术要求--纪念《变压器》杂志创刊40周年暨出版400期

概述了变压器发展中的一些新技术要求,澄清了变压器技术中的一些易误解的概念,并展望了变压器技术的发展趋势.